Identifiable Intangible Assets - (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Finite-Lived Intangible Assets and Goodwill [Line Items]
Goodwill	$ 19,298		$ 19,298		$ 11,371
Business Acquisition, Purchase Price Allocation, Goodwill Amount	7,939		7,939
Business Acquisition Purchase Price Allocation Goodwill Amount 2	(12)		(12)
Finite-Lived Intangible Assets, Gross	73,587		73,587		72,034
Finite-Lived Intangible Assets, Accumulated Amortization	60,936		60,936		59,676
Intangible Assets, Net (Excluding Goodwill)	12,651		12,651		12,358
Amortization of Intangible Assets	648	416	1,264	832
Future Amortization Expense, Remainder of Fiscal Year	1,328		1,328
Future Amortization Expense, Year One	2,400		2,400
Future Amortization Expense, Year Two	2,028		2,028
Future Amortization Expense, Year Three	1,919		1,919
Future Amortization Expense, Year Four	1,531		1,531
Future Amortization Expense, Year Five	1,095		1,095
Developed Technology Rights [Member]
Finite-Lived Intangible Assets and Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross	59,735		59,735		58,961
Finite-Lived Intangible Assets, Accumulated Amortization	50,416		50,416		49,358
Intangible Assets, Net (Excluding Goodwill)	9,319		9,319		9,603
Customer Relationships [Member]
Finite-Lived Intangible Assets and Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross	9,491		9,491		8,712
Finite-Lived Intangible Assets, Accumulated Amortization	7,253		7,253		7,102
Intangible Assets, Net (Excluding Goodwill)	2,238		2,238		1,610
Trade Names [Member]
Finite-Lived Intangible Assets and Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross	4,361		4,361		4,361
Finite-Lived Intangible Assets, Accumulated Amortization	3,267		3,267		3,216
Intangible Assets, Net (Excluding Goodwill)	$ 1,094		$ 1,094		$ 1,145